JPH04218933A - Flexible circuit board and liquid crystal display device - Google Patents

Abstract

PURPOSE:To dispense with a 2-layer printed circuit board by forming output terminals for connections with a display device on one side of a flexible printed circuit board carrying a LSI chip and forming input terminals on the two sides which are perpendicular to the selected side. CONSTITUTION:Input terminals 2a-h for a flexible printed circuit board (COF) 4 are formed to be perpendicular to the output terminals 1 and parallel to other input terminals. After that, the signal wires 5B-G of a printed circuit board 8 which is a one-sided board not requiring upper and lower continuity achieved by through holes are soldered to the input terminals 2a-h of COF 4. Further, a liquid crystal device 7 and output terminals 1 are connected by an anisotropic conductive adhesive agent.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit board used in a liquid crystal display device.

0002

[Prior Art] A flexible circuit board (hereinafter abbreviated as COF) used in a conventional liquid crystal display device, etc. is equipped with an LSI chip for driving a liquid crystal display element, and has input terminals a to h as shown in FIG. Since 2 was placed parallel to output terminal 1, vertical continuity was established through through hole 6.
Input terminals a to h and signal lines B to G were connected using a layered substrate.

FIG. 5 is a schematic diagram of FIG. 4 showing an expanded state of the liquid crystal display device.
Fold the COF 4 to the back side of the liquid crystal display element 7 and connect Z and Z by soldering or the like.

0004

However, in the prior art described above, since the input terminals 2a to 2h of the COF 4 are arranged parallel to the signal lines B to G, the terminals a to h and the signal line 5B are
When connecting .about.G, a two-layer board with upper and lower conduction through through holes 6 is required to avoid perpendicular crossing with other signal lines. Therefore, a liquid crystal display device using such a two-layer substrate has the problem of being expensive. SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide a flexible circuit board that does not require a two-layer board and an inexpensive and highly reliable liquid crystal display device.

[0005]

[Means for Solving the Problems] The flexible circuit board of the present invention is a flexible circuit board on which an LSI chip is mounted, in which an output terminal connected to a display element, etc. is formed on one side, and two output terminals perpendicular to the one side are formed. It is characterized in that input terminals are formed on the sides.

The liquid crystal display device of the present invention uses a flexible circuit board having an output terminal connected to a display element etc. on one side and input terminals formed on two sides orthogonal to the one side. The display device is characterized in that the electrode terminal of the display element and the output terminal are electrically connected, and the signal line of the substrate and the input terminal are electrically connected.

[0007]

[Example] Figure 1 shows a COF4 in an example of the present invention.
This is a wiring diagram in which the input terminals a to h of the input terminals 2 are arranged perpendicularly to the output terminal 1 and the input terminals are arranged parallel to each other. The reason that a and h of the input terminals 2 are located on the same line is to connect the COFs 4 in cascade. Furthermore, if cascade connection is not used, input terminals can be arranged in one direction, either left or right.

FIG. 2 is a detailed diagram of a liquid crystal display device using the above-mentioned COF. Since the input terminals are arranged perpendicularly to the output and each input terminal is parallel to each other, the signal lines B to G of the signal lines 5 On the other hand, the substrate 8 that is parallel to and connected to the substrate 8 is a single-sided substrate that does not require vertical conduction through through holes. signal line 5
The input terminals a to h of the COF and the input terminals a to h of the COF are connected by soldering or the like. The liquid crystal display element 7 and the output terminal 1 are connected with an anisotropic conductive adhesive or the like.

FIG. 3 is a schematic diagram of FIG. 2 and shows the liquid crystal display device in an expanded state.
The substrate 8, COF and 4 are bent onto the back side of the liquid crystal display element 7, and Z and Z' are connected by soldering or the like.

With the above configuration, the substrate 8
Since it is only necessary to form a pattern on one side, manufacturing is easy and the process can be shortened. Therefore, cost reduction of liquid crystal display elements has been achieved.

[0011] Also, the LSI chip 3 mounted on the COF 4
Since the COF 4 is positioned above the substrate 8, it is supported by the substrate 8 during the process of bending the COF 4 to complete the liquid crystal display element, and has the effect of preventing defects caused by bending and impact to the LSI chip 3. ing.

Furthermore, since the connection between the COF 4 and the substrate 8 is made on two opposing sides of one COF, the connection is strong.

[0013]

As described above, according to the present invention, it is possible to use a substrate with a pattern formed on only one side, thereby making it possible to reduce costs.

Furthermore, the connection between the COF and the substrate becomes strong, and a highly reliable liquid crystal display device can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a flexible circuit board of the present invention.

FIG. 2 is an enlarged view of main parts of the liquid crystal display device of the present invention.

FIG. 3 is a schematic diagram of a liquid crystal display device of the present invention.

[Figure 4] Enlarged view of main parts of a conventional liquid crystal display device

FIG. 5 is a schematic diagram of a conventional liquid crystal display device.

[Explanation of symbols]

1 Output terminal 2 Input terminal 3 LSI chip 4 COF 5 Signal line 6 Through hole 7 Liquid crystal display element 8 Board

Claims (2)

[Claims] Claim 1: In a flexible circuit board on which an LSI chip is mounted, an output terminal connected to a display element, etc. is formed on one side, and input terminals are formed on two sides perpendicular to the one side. Features a flexible circuit board. 2. Using a flexible circuit board having an output terminal connected to a display element, etc. formed on one side, and input terminals formed on two sides orthogonal to the one side, electrode terminals of a liquid crystal display element are formed. and the output terminal, and a signal line of a substrate and the input terminal are electrically connected.